obama spoke mostly to the moderator, jim lehrer of pbs. >> we still have trillion dollar deficits. the cbo says we'll have a trillion dollar deficit each of the next four years. >> reporter: these two men, they are virtually strangers to each other personally. they've only met in person three times before tonight. most recently, in passing, on a debate stage in new hampshire way back in 2008, when republicans followed democrats in debate three days before the primaries. and there was this brief encounter on the campaign trail in 2007. >> good luck to you today. >> reporter: and while they have both reached the pinnacle of party politics, they are so different. their talents and their paths to power and their debate styles. so much at stake on that stage tonight. this showdown comes at what might be the critical moment in this campaign. a hinge of political history. polls show the race tightening, just 34 days left in this campaign. and you can already sense in the crowds the special energy of the home stretch. but tonight, surprisingly, and in contrast to the daily scrap on the tra